LANSING, Mich. (AP) — Republican consultant Mark Pischea and Democratic consultant Dianne Byrum haven’t agreed on much over the years, including whether the state should loosen embryonic stem cell research restrictions or cut the number of lawmakers and state Supreme Court justices.

Sometimes the differences have been downright personal, such as the 2004 attack ad Pischea’s firm aired against Byrum when she was running for re-election to the state House.

Now the two long-time combatants have joined forces to promote a measure that would require Michigan’s major utilities to get 25 percent of their power from renewable sources by 2025. Signatures are being collected to get the measure on the November ballot, which would replace the current requirement that utilities get 10 percent from renewables by 2015.

Both consultants see the measure as a way to create more jobs in Michigan by expanding the state’s manufacturing base into areas increasingly important in the global economy. But they come at it from different angles tied to the groups they represent.

For Pischea and fellow partners Steve Linder and former Michigan Republican Party executive director Jeff Timmer at The Sterling Corp., it’s an economic issue, a way to help companies such as Dow Chemical Co. and Dowding Industries Inc. that have made significant “green energy” investments in solar products and wind turbines.

Byrum sees the renewable energy proposal as a chance to be more environmentally friendly and encourage innovation in green technology. She started Byrum & Fisk Advocacy Communications in East Lansing five years ago with former House Democratic political director Mark Fisk after 24 years as a county commissioner and state lawmaker. She also helps oversee her family’s hardware stores.

“We can disagree on climate change and still support this,” Pischea said. “This kind of collaborative can’t work on every issue. There are some issues that truly are partisan or ideological, and we just aren’t ever going to agree. But then there are issues like this.”

It hasn’t all been smooth sailing. Sterling customers have questioned if the company has misplaced its free-market beliefs. Byrum says she never would have imagined when she was a lawmaker that she’d join hands with Sterling.

The two consulting firms have assured clients that they remain fierce opponents on a variety of issues, including partisan legislative races.

“They work on the most conservative issues. We are always on the progressive side of the issues,” Byrum said. “They’re not ‘Republican lite’ and we’re clearly not ‘Democratic lite.’ We wear our stripes on our shirt sleeves, and we’re very proud of it.”

It’s a sentiment echoed by Pischea.

“We still want to be a Republican firm. We don’t want to be nonpartisan. We don’t want to be bipartisan,” he said. “Neither one of us wants to change our stripes.”

Michigan Environmental Council spokesman Hugh McDiarmid Jr., whose organization is promoting the renewable energy ballot proposal, says he wishes the political arena had more examples of the Sterling-Byrum & Fisk collaboration.

“It is remarkable in a certain sense to see Mark Fisk and Mark Pischea sitting at the same conference table agreeing on these issues,” McDiarmid said. “It’s a little bit heartening, I guess, given that a lot of the work that we do is in the political trenches … where the usual suspects line up on the usual sides most of the time.”

Back in the days when Byrum — the House’s first female Democratic leader — was helping Democrats regain control of the state House, Sterling was the enemy. The GOP firm used Byrum’s trademark billboards showing her holding a coffee cup and the words, “If it’s Thursday, it must be coffee with Dianne” as the basis of an attack ad alleging her leadership role was keeping her so busy she was out of touch with constituents in her district south of Lansing. The ads showed a coffee house growing dusty and full of cobwebs.

“I was spitting mad,” Byrum recalls. “I was still doing coffee hours, so it wasn’t exactly accurate. … There definitely was some history there.”

But when Pischea walked into one of their early renewable energy meetings last year with a copy of the ad in hand, Byrum wasn’t holding any grudges. After all, she had beaten the Republican Sterling hoped would defeat her.

“We get together and we laugh about the ads we’ve run against each other,” Pischea said. “There’s lots of places we disagree, and we have a lot of fun at some of those meetings because we’re all pretty passionate people.”

They’re working now to win support for the ballot proposal from their varied constituencies ranging from business groups to environmentalists. Pischea and Byrum both said the bipartisan approach is necessary because they each know how to get through to people in their own camps who might resist the same message coming from the other side.

At least on the need for more renewable energy, their relationship is like the sheepdog and coyote in the old Warner Bros. cartoon — fierce when they need to compete, but friendly when they can put their differences aside.

“We get along personally,” Pischea said. “We have families that we love, communities that we belong to. When you have that as a foundation, disagreeing on the issues isn’t as big of a deal.”